Synchronous Serial Interface bus driver
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This directory holds the SSI bus drivers. Basically, a SSI bus consists
of the following signals:
stxd Transmit data
srxd Receive data
sclk Clock
sfrm Frame
Chip selects (1 - n)
There may be more than one device on a SSI bus, and each device can
have different timing requirements. There are several frame formats:
1. Texas Instruments Synchronous Serial Frame format
sclk ____~_~_~_~_~_~_~_~____
sfrm ____~~_________________
stxd ------bn..........b0---
srxd ------bn..........b0---
- data latched in on the falling edge of the clock
- data shifted out on the rising edge of the clock
2. Motorola SPI frame format
sclk ______~_~_~_~_~_~_~____
sfrm ~~~~________________~~~
stxd -----bn..........b0----
srxd ----.bn..........b0----
- data latched in on the rising edge of the clock
- data shifted out on the falling edge of the clock, or falling edge
of sfrm
3. National Microwire format
sclk ______~_~_~_~_~_~_~_~_~_~_~_~_~_____
sfrm ~~~~_____________________________~~~
stxd -----bn......b0---------------------
srxd -----------------bn..........b0.----
- data latched in on the rising edge of the clock
- data shifted out on the falling edge of the clock
- half duplex, one clock between transmission and reception
Types of devices
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The following types of devices can be found on a SSP bus:
Sound chips
Keyboard devices
Touch screen devices
Keyboard
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TX:
0. Format: cfglen = 8, framelen = 8, clkpol = 1, clk < 250kHz
1. select device
2. keyboard responds asserting key_atn
3. wait 0.1ms to 5ms
4. transmit data byte
5. wait >= 150us
6. repeat step 4 until all data sent
7. deselect device
8. keyboard responds de-asserting key_atn
9. wait >= 120us
RX:
0. Format: cfglen = 8, framelen = 8, clkpol = 1, clk < 250kHz
1. keyboard asserts key_atn
2. select device after 0.1ms < 5ms
3. read data byte
4. wait 150us
5. if key_atn still asserted, goto 3
6. deselect device
7. wait >= 120us
Download Driver Pack
After your driver has been downloaded, follow these simple steps to install it.
Expand the archive file (if the download file is in zip or rar format).
If the expanded file has an .exe extension, double click it and follow the installation instructions.
Otherwise, open Device Manager by right-clicking the Start menu and selecting Device Manager.
Find the device and model you want to update in the device list.
Double-click on it to open the Properties dialog box.
From the Properties dialog box, select the Driver tab.
Click the Update Driver button, then follow the instructions.
Very important: You must reboot your system to ensure that any driver updates have taken effect.
For more help, visit our Driver Support section for step-by-step videos on how to install drivers for every file type.